IHI PS 105: Introduction to Patient Safety Study Guide
Course Overview: PS 105 focuses on building a foundational understanding of patient
safety. It moves from the historical context of the patient safety movement to modern,
systems-based approaches for preventing error, reducing harm, and building a culture
of safety within healthcare organizations.
Module 1: The Case for Patient Safety & The Nature of Error
1. What is the definition of patient safety?
ANSWER ✓ Patient safety is a discipline in the health care sector that applies safety
science methods toward the goal of achieving a trustworthy system of health care
delivery. It is also an attribute of health care systems; it minimizes the incidence and
impact of, and maximizes recovery from, adverse events.
2. According to the landmark "To Err Is Human" report, what was the estimated
annual number of deaths in US hospitals due to medical error?
ANSWER ✓ The 1999 Institute of Medicine report estimated that between 44,000 and
98,000 people die each year in US hospitals as a result of medical errors.
3. What is the main difference between an adverse event and a preventable
adverse event?
ANSWER ✓ An adverse event is an injury caused by medical management rather than
the underlying disease. A preventable adverse event is an adverse event that could have
been avoided given the current state of medical knowledge.
4. What is a "never event" as defined by the National Quality Forum (NQF)?
, ANSWER ✓ "Never events" are serious, preventable adverse events that should never
occur in a healthcare setting. Examples include surgery on the wrong body part, foreign
object left in a body after surgery, or patient death from a medication error.
5. What is the "Swiss Cheese Model" of accident causation?
ANSWER ✓ It is a model developed by James Reason that illustrates how accidents are
often the result of a series of failures (holes in layers of Swiss cheese) that line up. The
layers represent defenses, barriers, and safeguards in the system. A hazard passes
through when the holes in all layers momentarily align.
6. According to systems thinking, where should the focus be after an error occurs:
on the individual or on the system?
ANSWER ✓ The focus should be on the system. Systems thinking posists that while
individuals must be accountable, errors are often the result of poorly designed systems
that fail to protect against human fallibility. Blaming individuals does not prevent the
error from happening again.
7. What is the difference between an active error and a latent error?
ANSWER ✓ An active error is an error that occurs at the point of contact between a
human and a system (e.g., a nurse administering the wrong drug). Its effects are felt
almost immediately. A latent error is a hidden flaw in the system or organization (e.g.,
poor equipment design, understaffing) that may lie dormant for a long time until it
contributes to an active error.
8. Why is blaming individuals for errors counterproductive to improving safety?
ANSWER ✓ It creates a culture of fear where staff are afraid to report errors. This
prevents the organization from learning about system flaws, making it impossible to fix
them and prevent future harm.
9. What is a "second victim"?
Course Overview: PS 105 focuses on building a foundational understanding of patient
safety. It moves from the historical context of the patient safety movement to modern,
systems-based approaches for preventing error, reducing harm, and building a culture
of safety within healthcare organizations.
Module 1: The Case for Patient Safety & The Nature of Error
1. What is the definition of patient safety?
ANSWER ✓ Patient safety is a discipline in the health care sector that applies safety
science methods toward the goal of achieving a trustworthy system of health care
delivery. It is also an attribute of health care systems; it minimizes the incidence and
impact of, and maximizes recovery from, adverse events.
2. According to the landmark "To Err Is Human" report, what was the estimated
annual number of deaths in US hospitals due to medical error?
ANSWER ✓ The 1999 Institute of Medicine report estimated that between 44,000 and
98,000 people die each year in US hospitals as a result of medical errors.
3. What is the main difference between an adverse event and a preventable
adverse event?
ANSWER ✓ An adverse event is an injury caused by medical management rather than
the underlying disease. A preventable adverse event is an adverse event that could have
been avoided given the current state of medical knowledge.
4. What is a "never event" as defined by the National Quality Forum (NQF)?
, ANSWER ✓ "Never events" are serious, preventable adverse events that should never
occur in a healthcare setting. Examples include surgery on the wrong body part, foreign
object left in a body after surgery, or patient death from a medication error.
5. What is the "Swiss Cheese Model" of accident causation?
ANSWER ✓ It is a model developed by James Reason that illustrates how accidents are
often the result of a series of failures (holes in layers of Swiss cheese) that line up. The
layers represent defenses, barriers, and safeguards in the system. A hazard passes
through when the holes in all layers momentarily align.
6. According to systems thinking, where should the focus be after an error occurs:
on the individual or on the system?
ANSWER ✓ The focus should be on the system. Systems thinking posists that while
individuals must be accountable, errors are often the result of poorly designed systems
that fail to protect against human fallibility. Blaming individuals does not prevent the
error from happening again.
7. What is the difference between an active error and a latent error?
ANSWER ✓ An active error is an error that occurs at the point of contact between a
human and a system (e.g., a nurse administering the wrong drug). Its effects are felt
almost immediately. A latent error is a hidden flaw in the system or organization (e.g.,
poor equipment design, understaffing) that may lie dormant for a long time until it
contributes to an active error.
8. Why is blaming individuals for errors counterproductive to improving safety?
ANSWER ✓ It creates a culture of fear where staff are afraid to report errors. This
prevents the organization from learning about system flaws, making it impossible to fix
them and prevent future harm.
9. What is a "second victim"?
